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    <title>Document</title>
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<body>
    <input type="text" name="" id="inp">
    <script>
        let inp = document.querySelector('#inp');


        function debounce(fn, delay = 500) {
            let time = null;
            return function(e) {
                if (time) {
                    clearTimeout(time)
                }
                time = setTimeout(() => {
                    console.log(e.keyCode);
                    fn.call(this, e);
                    time = null;
                }, delay);
            }
        }


        inp.onkeyup = debounce(function(e) {
            console.log(e);
            console.log(this);
        });
    </script>
</body>

</html>